Caliban is the 20th moon of Uranus in order from the planet. It was discovered, together with Sycorax, on 6 September 1997 by Brett J. Gladman, Philip D. Nicholson, Joseph A. Burns, and John J. Kavelaars using the 5-meter Hale Telescope and given the temporary designation S/1997 U1. It was later named after the dark character in Shakespeare's play The Tempest and is also known as Uranus XVI. Caliban is an irregular moon with a highly inclined, retrograde orbit. Like Sycorax, it has a reddish hue, suggesting it may have come from the Kuiper Belt.